convertCase converts arrays to objects #80
Description
E.g. an attribute with the value [1,2,3,4,5] will be converted to {0: 1, 1: 2, 2: 3...}, which should not happen.
Can be fixed with an extra check for data is array:
https://github.com/stefanvanherwijnen/json-api-serializer/commit/656ad5bbbf9d071903fb71454c73b798a5bbcc93